Design method for active disturbance rejection roll controller of vehicle under disturbance of complex sea conditions

ABSTRACT

The present disclosure provides a design method for an active disturbance rejection roll controller of a vehicle under disturbance of complex sea conditions, including: step 1: establishing a vehicle roll attitude control model; step 2: designing an active disturbance rejection controller (ADRC) on the basis of the control model in step 1 and a pole placement method; and step 3: performing an active disturbance rejection roll control by using the active disturbance rejection controller in step 2. The present disclosure solves the problem of a stable control of the vehicle under the disturbance of the complex sea conditions.

CROSS REFERENCE TO RELATED APPLICATION

This patent application claims the benefit and priority of ChinesePatent Application No. 202111149593.4, entitled “DESIGN METHOD FORACTIVE DISTURBANCE REJECTION ROLL CONTROLLER OF VEHICLE UNDERDISTURBANCE OF COMPLEX SEA CONDITIONS” filed on Sep. 29, 2021, thedisclosure of which is incorporated by reference herein in its entiretyas part of the present application.

TECHNICAL FIELD

The present disclosure relates to the field of vehicle control, andspecifically to a design method for an active disturbance rejection rollcontroller of a vehicle under disturbance of complex sea conditions.

BACKGROUND ART

At present, for the problem of roll control of the vehicle under thedisturbance of the complex sea conditions, the performance of aproportional-integral-derivative (PID) controller deteriorates and doesnot meet requirements of use under extreme operating conditions.Moreover, in a nonlinear control method adopted, some controllers dependon a specific model of disturbance, and some controllers have morecumbersome design methods, thereby being not conducive to engineeringimplementation. The present disclosure designs a linear extended stateobserver, and adopts a relatively simple and effective parameter settingmethod, so that the vehicle has good control performance under theaction of strong external disturbance.

SUMMARY

The present disclosure provides a design method for an activedisturbance rejection roll controller of a vehicle under disturbance ofcomplex sea conditions, solving a problem of stable control of thevehicle under the disturbance of the complex sea conditions.

The present disclosure is implemented by the following technicalsolutions:

A design method for an active disturbance rejection roll controller of avehicle under disturbance of complex sea conditions, where an activedisturbance rejection roll control method for the vehicle includes thefollowing steps:

step 1: establishing a vehicle roll attitude control model;

step 2: designing an active disturbance rejection controller (ADRC) onthe basis of the control model in step 1 and a pole placement method;and

step 3: performing an active disturbance rejection roll control by usingthe active disturbance rejection controller in step 2.

Furthermore, in step 1, according to a theorem of momentum and moment ofmomentum, an equation of the roll motion is obtained as follows:

$\begin{matrix}\left\{ \begin{matrix}{{{J_{x}{\overset{.}{w}}_{x}} + {\left( {J_{z} - J_{y}} \right)w_{y}w_{x}}} = {{A_{m_{x}}^{\beta}v^{2}\beta} - {A_{m_{x}}^{\delta}v^{2}\delta_{d}} - {A_{m_{x}}^{w}v^{2}w_{x}} + {A_{m_{xp}}v^{2}} - {\lambda_{44}{\overset{.}{w}}_{x}} - {{B\left( {{z_{b}\cos\varphi} + {h\sin\varphi}} \right)}\cos\theta} + M_{d}}} \\{\varphi = {w_{x} - {\left( {{w_{y}\cos\varphi} - {w_{z}\sin\varphi}} \right)\tan\theta}}} \\{{\cos\Theta\sin\Phi} = {{\cos\beta\cos\theta\sin\varphi} - {\sin\alpha\sin\beta\cos\theta\cos\varphi} + {\cos\alpha\sin\beta\sin\theta}}}\end{matrix} \right. & (1)\end{matrix}$

where, a simplifying assumption is made on the equation according to atypical trajectory, that is, the equation is simplified under threeconditions of linearization, horizontal straight trajectory and axialsymmetry of the vehicle, and the simplified equation of the roll motionis as follows:

$\begin{matrix}{{{\left( {J_{x} + \lambda_{44}} \right)\frac{dw_{x}}{dt}} + {\frac{1}{2}\rho v^{2}SLm_{x}^{wx}w_{x_{1}}}} = {{\frac{1}{2}\rho v^{2}SLm_{x}^{\delta_{d}}\delta_{d}} + M_{d}}} & (2)\end{matrix}$

where, J_(x) is a moment of inertia of the vehicle along an x axis, λ₄₄is additional mass of the vehicle along the x axis, P is density of anenvironment where the vehicle is located, v is a velocity of thevehicle, S is a characteristic area of the vehicle, L is acharacteristic length of the vehicle, m_(x) ^(wx) is a roll momentdamping constant of the vehicle, w_(x) is an angular velocity in roll ofthe vehicle, m_(x) ^(δ) ^(d) is a relative derivative of a roll controlmoment of the vehicle, δ_(d) is an equivalent roll rudder deflectionangle of the vehicle, and M_(d) is a disturbance moment caused by thecomplex sea conditions around the vehicle; and

a transfer function of a roll angle to a roll rudder deflection angle isas follows:

$\begin{matrix}{{G_{\varphi}(s)} = {\frac{\frac{1}{2}\rho v^{2}SLm_{x}^{\delta_{d}}}{{\left( {J_{x} + \lambda_{44}} \right)s} - {\frac{1}{2}\rho v^{2}SLm_{x}^{wx}}}\frac{1}{s}}} & (3)\end{matrix}$

Furthermore, designing the active disturbance rejection controller instep 2 specifically includes:

step 2.1: designing a linear extended state observer (LESO)without anobject model;

step 2.2: designing a linear state error feedback (LSEF) controller;

step 2.3: performing a simulation analysis on the LESO in step 2.1 andthe LSEF controller in step 2.2; and

step 2.4: verifying performance of the active disturbance rejectioncontroller (ADRC).

Furthermore, in step 2.1, with making y→φ and w representing totaldisturbance, a vehicle roll control system is described as follows:

ÿ−a ₁ {dot over (y)}−a ₀ y+w+bu  (4)

where, y is a roll angle, {dot over (y)} is an angular velocity in roll,ÿ is an acceleration of the roll angle, u is an input of controlquantity, b is a relative coefficient of control, a₀ is a relativecoefficient of the roll angle, and a₁ is a relative coefficient of theangular velocity in roll;

the total disturbance is set as follows:

f(y, {dot over (y)}, w, t)=−a ₁ {dot over (y)}−a ₀ y+w+(b−b ₀)u  (5)

formula (5) is rewritten as follows:

ÿ=f+b ₀ u  (6)

by setting state variables as follows: x₁=y, x₂={dot over (y)}, andx₃=f, a continuous extended state observer is obtained as follows:

{dot over (x)}=Ax+Bu+E{dot over (f)}   (7)

where,

${A = \begin{bmatrix}0 & 1 & 0 \\0 & 0 & 1 \\0 & 0 & 0\end{bmatrix}},{B = \begin{bmatrix}0 \\b_{0} \\0\end{bmatrix}},{{{{and}{}E} = \begin{bmatrix}0 \\0 \\1\end{bmatrix}};}$

a corresponding LESO is:

$\begin{matrix}\left\{ \begin{matrix}{\overset{.}{z} = {{Ax} + {Bu} + {L\left( {y - \overset{\hat{}}{y}} \right)}}} \\{\overset{\hat{}}{y} = {Cz}}\end{matrix} \right. & (8)\end{matrix}$

where, C=[1 0 0], and L=[L₁ L₂ L₃]^(T) is an error feedback control gainmatrix of the observer;

a characteristic equation of the formula is:

λ(s)=|sI−(A−LC)|  (9)

after parameterization, a pole of the characteristic equation isdesigned as follows:

λ(s)=(s+w ₀)(s+k ₀ w ₀)(s+k ₂ w ₀)   (10)

where, w₀ is a pole of a designed extended state observer, and k₁ and k₂are pole placement coefficients of the extended state observer; and

a gain matrix of the extended state observer is obtained as follows:

$\begin{matrix}{L = \begin{bmatrix}{\left( {k_{1} + k_{2} + 1} \right)w_{0}} \\{\left( {k_{1} + k_{2} + {k_{1}k_{2}}} \right)w_{0}^{2}} \\{\left( {k_{1}k_{2}} \right)w_{0}^{3}}\end{bmatrix}} & (11)\end{matrix}$

Furthermore, in step 2.2, the LSEF adopts a controller of a linearproportional and derivative (PD) combination, z₁→y, z₂→{dot over (y)};and

a form of the controller is:

u ₀ =k _(p)(z _(c) −z ₁)−k _(d) z ₂   (12)

where, u₀ is final control output, z_(c) is an expected roll angle, z₁is a roll angle of the vehicle in a current state, and z₂ is a rollangular velocity of the vehicle in the current state;

a closed-loop transfer function is:

$\begin{matrix}{{G(s)} = \frac{k_{p}}{s^{2} + {k_{d}s} + k_{p}}} & (13)\end{matrix}$

where, k_(p) and k_(d) are controller parameters needing to be designed,and, by selecting the pole of the transfer function of the controllerand placing the pole at different positions w_(c), and k₃w_(c), w_(c)>1,k₃>1, the controller parameters are obtained as follows:

k _(p) =k ₃ w _(c) ²

k _(d)=(k ₃+1)w _(c)   (14)

after parametric design, six parameters to be adjusted in the ADRC arew₀, w_(c), b₀, k₁, k₂, k₃, where w₀ is the pole of the extended stateobserver, w_(c) is a pole of the controller, b₀ is a controlcoefficient, k₁ and k₂ are the pole placement coefficients of theextended state observer, and k₃ is a pole placement coefficient of thecontroller.

The present disclosure has the following beneficial effects:

The active disturbance rejection controller under the complex seaconditions of the present disclosure has better control performance,quick response time, high control precision and good robustness, and maystably control a roll channel of the vehicle under unknown disturbance.

The linear extended state observer of the present disclosure does notdepend on a specific control model, has short convergence time andstable control performance, and may perform model compensation within ashort time.

The linear extended state observer of the present disclosure has bettercontrol performance, simple structure, remarkable effects, and strongoperability for parameter setting, and it is easy to be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of an ADRC in the presentdisclosure.

FIG. 2 is a schematic structural diagram of an extended state observerin the present disclosure.

FIG. 3 is a graph of ADRC output with an input signal as a unit stepsignal and an external disturbance as a constant disturbance in thepresent disclosure.

FIG. 4 is a graph of PID output with an input signal as a unit stepsignal and an external disturbance as a constant disturbance in thepresent disclosure.

FIG. 5 is a graph of ADRC rudder deflection angle with an input signalas a unit step signal and an external disturbance as a constantdisturbance in the present disclosure.

FIG. 6 is a graph of PID rudder deflection angle with an input signal asa unit step signal and an external disturbance as a constant disturbancein the present disclosure.

FIG. 7 is a graph of ADRC output with an input signal as a unit stepsignal and an external disturbance as a periodic disturbance in thepresent disclosure.

FIG. 8 is a graph of PID output with an input signal as a unit stepsignal and an external disturbance as a periodic disturbance in thepresent disclosure.

FIG. 9 is a graph of ADRC rudder deflection angle with an input signalas a unit step signal and an external disturbance as a periodicdisturbance in the present disclosure.

FIG. 10 is a graph of PID rudder deflection angle with an input signalas a unit step signal and an external disturbance as a periodicdisturbance in the present disclosure.

FIG. 11 is a graph of ADRC output with an input signal as a squaresignal and an external disturbance as a periodic disturbance in thepresent disclosure.

FIG. 12 is a graph of PID output with an input signal as a square signaland an external disturbance as a periodic disturbance in the presentdisclosure.

FIG. 13 is a graph of ADRC rudder deflection angle with an input signalas a square signal and an external disturbance as a periodic disturbancein the present disclosure.

FIG. 14 is a graph of PID rudder deflection angle with an input signalas a square signal and an external disturbance as a periodic disturbancein the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions in the embodiments of the present disclosure areclearly and completely described below with reference to theaccompanying drawings in the embodiments of the present disclosure.Apparently, the described embodiments are merely some rather than all ofthe embodiments of the present disclosure. On the basis of theembodiments of the present disclosure, all other embodiments derived bya person of ordinary skill in the art, without involving any creativeeffort, fall within the scope of protection of the present disclosure.

An active disturbance rejection roll control method for a vehicle underdisturbance of complex sea conditions includes the following steps:

step 1: establishing a vehicle roll attitude control model;

step 2: designing an active disturbance rejection controller (ADRC) onthe basis of the control model in step 1 and a pole placement method;and

step 3: performing an active disturbance rejection roll control by usingthe active disturbance rejection controller in step 2.

Furthermore, in step 1, according to a theorem of momentum and moment ofmomentum, an equation of the roll motion is obtained as follows:

$\begin{matrix}\left\{ \begin{matrix}{{{J_{x}{\overset{.}{w}}_{x}} + {\left( {J_{z} - J_{y}} \right)w_{y}w_{x}}} = {{A_{m_{x}}^{\beta}v^{2}\beta} - {A_{m_{x}}^{\delta}v^{2}\delta_{d}} - {A_{m_{x}}^{w}v^{2}w_{x}} + {A_{m_{xp}}v^{2}} - {\lambda_{44}{\overset{.}{w}}_{x}} - {{B\left( {{z_{b}\cos\varphi} + {h\sin\varphi}} \right)}\cos\theta} + M_{d}}} \\{\varphi = {w_{x} - {\left( {{w_{y}\cos\varphi} - {w_{z}\sin\varphi}} \right)\tan\theta}}} \\{{\cos\Theta\sin\Phi} = {{\cos\beta\cos\theta\sin\varphi} - {\sin\alpha\sin\beta\cos\theta\cos\varphi} + {\cos\alpha\sin\beta\sin\theta}}}\end{matrix} \right. & (1)\end{matrix}$

where, a simplifying assumption is made on the equation according to atypical trajectory, that is, the equation is simplified under threeconditions of linearization, horizontal straight trajectory and axialsymmetry of the vehicle, and the simplified equation of the roll motionis as follows:

$\begin{matrix}{{{\left( {J_{x} + \lambda_{44}} \right)\frac{dw_{x}}{dt}} + {\frac{1}{2}\rho v^{2}SLm_{x}^{wx}w_{x_{1}}}} = {{\frac{1}{2}\rho v^{2}SLm_{x}^{\delta_{d}}\delta_{d}} + M_{d}}} & (2)\end{matrix}$

where, J_(x) is a moment of inertia of the vehicle along an x axis, δ₄₄is additional mass of the vehicle along the x axis, P is density of anenvironment where the vehicle is located, v is a velocity of thevehicle, S is a characteristic area of the vehicle, L is acharacteristic length of the vehicle, m_(x) ^(wx) is roll moment dampingconstant of the vehicle, w_(x) is an angular velocity in roll of thevehicle, m_(x) ^(δ) ^(d) is a relative derivative of a roll controlmoment of the vehicle, δ_(d) is an equivalent roll rudder deflectionangle of the vehicle, and M_(d) is a disturbance moment caused by thecomplex sea conditions around the vehicle.

To study an individual roll motion, the simplifying assumption is madeaccording to the typical trajectory:

(1) the equation is linearized by a small-angle assumption;

(2) the horizontal straight trajectory is considered; and

(3) the vehicle is axisymmetric, a propeller is balanced, and a centerof gravity is not shifted.

A transfer function of a roll angle to a roll rudder deflection angle isas follows:

$\begin{matrix}{{G_{\varphi}(s)} = {\frac{\frac{1}{2}\rho v^{2}SLm_{x}^{\delta_{d}}}{{\left( {J_{x} + \lambda_{44}} \right)s} - {\frac{1}{2}\rho v^{2}SLm_{x}^{wx}}}\frac{1}{s}}} & (3)\end{matrix}$

Furthermore, the design of the active disturbance rejection controllerin step 2 specifically includes the following steps:

step 2.1: designing a linear extended state observer (LESO) without anobject model;

step 2.2: designing a linear state error feedback (LSEF) controller;

step 2.3: performing a simulation analysis on the LESO in step 2.1 andthe LSEF controller in step 2.2; and

step 2.4: verifying performance of the active disturbance rejectioncontroller (ADRC).

Furthermore, in step 2.1, with making y→φ and w representing totaldisturbance, a vehicle roll control system is described as follows:

ÿ−a ₁ {dot over (y)}−a ₀ y+w+bu   (4)

where, y is a roll angle, {dot over (y)}) is an angular velocity inroll, ÿ is an acceleration of the roll angle, u is an input of controlquantity, b is a relative coefficient of control, a₀ is a relativecoefficient of the roll angle, and a₁ is a relative coefficient of theangular velocity in roll.

The total disturbance is set as follows:

f(y, {dot over (y)}, w, t)=−a ₁ {dot over (y)}−a ₀ y+w+(b−b ₀)u   (5)

Formula (5) is rewritten as follows:

ÿ=f+b ₀ u   (6)

By setting state variables as follows: x₁=y, x₂={dot over (y)}, and x₃=f, a continuous extended state observer is obtained as follows:

{dot over (x)}=Ax+Bu+E{dot over (f)}  (7)

${A = \begin{bmatrix}0 & 1 & 0 \\0 & 0 & 1 \\0 & 0 & 0\end{bmatrix}},{B = \begin{bmatrix}0 \\b_{0} \\0\end{bmatrix}},{{{and}E} = {\begin{bmatrix}0 \\0 \\1\end{bmatrix}.}}$

where,

The corresponding LESO is:

$\begin{matrix}\left\{ \begin{matrix}{\overset{.}{z} = {{Ax} + {Bu} + {L\left( {y - \overset{\hat{}}{y}} \right)}}} \\{\overset{\hat{}}{y} = {Cz}}\end{matrix} \right. & (8)\end{matrix}$

where, C=[1 0 0], and L=[L₁L₂ L₃]^(T) is an error feedback control gainmatrix of the observer.

A characteristic equation of the formula is:

λ(s)=|sI−(A−LC)|  (9)

After parameterization, a pole of the characteristic equation isdesigned as follows:

λ(s)=(s+w ₀)(s+k ₀ w ₀)(s+k ₂ w ₀)   (10)

where, w₀ is a pole of a designed extended state observer, and k₁ and k₂are pole placement coefficients of the extended state observer; and

a gain matrix of the extended state observer is obtained as follows:

$\begin{matrix}{L = \begin{bmatrix}{\left( {k_{1} + k_{2} + 1} \right)w_{0}} \\{\left( {k_{1} + k_{2} + {k_{1}k_{2}}} \right)w_{0}^{2}} \\{\left( {k_{1}k_{2}} \right)w_{0}^{3}}\end{bmatrix}} & (11)\end{matrix}$

and derivative (PD) combination with the following form, z₁→y, z₂→{dotover (y)}; and the control law is:

u ₀=k _(p)(z _(c) −z ₁)−k _(d) z ₂   (12)

where u₀ is a final control output, z_(c) is an expected roll angle, z₁is a roll angle of the vehicle in a current state, and z₂ is an angularvelocity in roll of the vehicle in the current state;

a closed-loop transfer function is:

$\begin{matrix}{{G(s)} = \frac{k_{p}}{s^{2} + {k_{d}s} + k_{p}}} & (13)\end{matrix}$

where k_(p) and k_(d) are controller parameters needing to be designed,and, by selecting the pole of the transfer function of the controllerand placing the pole at different positions w_(c) and k₃w_(c) w_(c>)1,k₃>1, the controller parameters are obtained as follows:

k _(p) =k ₃ w _(c) ²

k _(d)=(k ₃+1)w _(c)   (14)

After parametric design, the ADRC has six parameters to be adjusted,namely w₀, w_(c), b₀, k₁, k₂, k₃, where w₀ is the pole of the extendedstate observer, w_(c) is a pole of the controller, b₀ is a controlcoefficient, k₁ and k₂ are the pole placement coefficients of theextended state observer, and k₃ is a pole placement coefficient of thecontroller.

The active disturbance rejection controller and the PID controller arerespectively configured to perform simulation, and an amplitude of theroll angle is set to be ±20°.

An input signal is a unit step signal, and an external disturbance is aconstant disturbance.

It can be seen from curves in FIG. 3 to FIG. 6 that an ADRC stepresponse signal converges faster and has no constant error, while a PIDconverges for a longer time and finally has a constant error, but ingeneral, a difference between control effects of the two is small underthis operating condition.

The input signal is a unit step signal, and the external disturbance isa periodic disturbance.

It can be seen from curves in FIG. 7 to FIG. 10 that under the periodicdisturbance, the ADRC step response signal converges faster, and finalerror convergence is smaller, while the PID controller has a largertracking error.

The input signal is a square signal, and the external disturbance is theperiodic disturbance.

It can be seen from curves in FIG. 11 to FIG. 14 that under the periodicdisturbance, a tracking error of the ADRC with respect to a periodicsquare signal is smaller and finally converges, while the PID controllerhas a larger tracking error.

1. A design method for an active disturbance rejection roll controllerof a vehicle under disturbance of complex sea conditions, wherein anactive disturbance rejection roll control method for the vehiclecomprises: step 1: establishing a vehicle roll attitude control model;step 2: designing an active disturbance rejection controller (ADRC) onthe basis of the control model in step 1 and a pole placement method;and step 3: performing an active disturbance rejection roll control byusing the active disturbance rejection controller in step
 2. 2. Thedesign method for the active disturbance rejection roll controller ofthe vehicle under the disturbance of the complex sea conditionsaccording to claim 1, wherein in step 1, according to a theorem ofmomentum and moment of momentum, an equation of the roll motion isobtained as follows: $\begin{matrix}\left\{ \begin{matrix}{{{J_{x}{\overset{.}{w}}_{x}} + {\left( {J_{z} - J_{y}} \right)w_{y}w_{x}}} = {{A_{m_{x}}^{\beta}v^{2}\beta} - {A_{m_{x}}^{\delta}v^{2}\delta_{d}} - {A_{m_{x}}^{w}v^{2}w_{x}} + {A_{m_{xp}}v^{2}} - {\lambda_{44}{\overset{.}{w}}_{x}} - {{B\left( {{z_{b}\cos\varphi} + {h\sin\varphi}} \right)}\cos\theta} + M_{d}}} \\{\varphi = {w_{x} - {\left( {{w_{y}\cos\varphi} - {w_{z}\sin\varphi}} \right)\tan\theta}}} \\{{\cos\Theta\sin\Phi} = {{\cos\beta\cos\theta\sin\varphi} - {\sin\alpha\sin\beta\cos\theta\cos\varphi} + {\cos\alpha\sin\beta\sin\theta}}}\end{matrix} \right. & (1)\end{matrix}$ wherein, a simplifying assumption is made on the equationaccording to a typical trajectory, that is, the equation is simplifiedunder three conditions of linearization, horizontal straight trajectoryand axial symmetry of the vehicle, and the simplified equation of rollmotion is as follows: $\begin{matrix}{{{\left( {J_{x} + \lambda_{44}} \right)\frac{dw_{x}}{dt}} + {\frac{1}{2}\rho v^{2}SLm_{x}^{wx}w_{x_{1}}}} = {{\frac{1}{2}\rho v^{2}SLm_{x}^{\delta_{d}}\delta_{d}} + M_{d}}} & (2)\end{matrix}$ where J_(x) is a moment of inertia of the vehicle along anx axis, λ₄₄ is additional mass of the vehicle along the x axis, P isdensity of an environment where the vehicle is located, v is a velocityof the vehicle, S is a characteristic area of the vehicle, L is acharacteristic length of the vehicle, m_(x) ^(wx) is a roll momentdamping constant of the vehicle, w_(x) is an angular velocity in roll ofthe vehicle, m_(x) ^(δ) ^(d) is a relative derivative of a roll controlmoment of the vehicle, δ_(d) is an equivalent roll rudder deflectionangle of the vehicle, and M_(d) is a disturbance moment caused by thecomplex sea conditions around the vehicle; and a transfer function of aroll angle to a roll rudder deflection angle is as follows:$\begin{matrix}{{G_{\varphi}(s)} = {\frac{\frac{1}{2}\rho v^{2}SLm_{x}^{\delta_{d}}}{{\left( {J_{x} + \lambda_{44}} \right)s} - {\frac{1}{2}\rho v^{2}SLm_{x}^{wx}}}\frac{1}{s}}} & (3)\end{matrix}$
 3. The design method for the active disturbance rejectionroll controller of the vehicle under the disturbance of the complex seaconditions according to claim 1, wherein designing the activedisturbance rejection controller in step 2 comprises: step 2.1:designing a linear extended state observer (LESO) without an objectmodel; step 2.2: designing a linear state error feedback (LSEF)controller; step 2.3: performing a simulation analysis on the LESO instep 2.1 and the LSEF controller in step 2.2; and step 2.4: verifyingperformance of the active disturbance rejection controller (ADRC). 4.The design method for the active disturbance rejection roll controllerof the vehicle under the disturbance of the complex sea conditionsaccording to claim 3, wherein in step 2.1, with making y→φ and wrepresenting total disturbance, a vehicle roll control system isdescribed as follows:ÿ−a ₁ {dot over (y)}−a ₀ y+w+bu   (4) wherein, y is a roll angle, {dotover (y)} is an angular velocity in roll, ÿ is an acceleration of theroll angle, u is an input of control quantity, b is a relativecoefficient of control, a₀ is a relative coefficient of the roll angle,and a₁ is a relative coefficient of the angular velocity in roll; thetotal disturbance is set as follows:f(y, {dot over (y)}, w, t)=−a ₁ {dot over (y)}−a ₀ y+w+(b−b ₀)u   (5)formula (5) is rewritten as follows:ÿ=f+b ₀ u   (6) by setting state variables as follows: x₁=y, x₂={dotover (y)}, and x₃=f, a continuous extended state observer is obtained asfollows:{dot over (x)}=Ax+Bu+E{dot over (f)}  (7) wherein, ${A = \begin{bmatrix}0 & 1 & 0 \\0 & 0 & 1 \\0 & 0 & 0\end{bmatrix}},{B = \begin{bmatrix}0 \\b_{0} \\0\end{bmatrix}},{{{{and}E} = \begin{bmatrix}0 \\0 \\1\end{bmatrix}};}$ a corresponding LESO is: $\begin{matrix}\left\{ \begin{matrix}{\overset{.}{z} = {{Ax} + {Bu} + {L\left( {y - \overset{\hat{}}{y}} \right)}}} \\{\overset{\hat{}}{y} = {Cz}}\end{matrix} \right. & (8)\end{matrix}$ wherein, C=[1 0 0], and L=[L₁L₂ L₃]^(T) is an errorfeedback control gain matrix of the observer; a characteristic equationof the formula is:λ(s)=|sI−(A−LC)|  (9) after parameterization, a pole of thecharacteristic equation is designed as follows:λ(s)=(s+w ₀)(s+k ₀ w ₀)(s+k ₂ w ₀)   (10) where w₀ is a pole of adesigned extended state observer, and k₁ and k₂ are pole placementcoefficients of the extended state observer; and a gain matrix of theextended state observer is obtained as follows: $\begin{matrix}{L = \begin{bmatrix}{\left( {k_{1} + k_{2} + 1} \right)w_{0}} \\{\left( {k_{1} + k_{2} + {k_{1}k_{2}}} \right)w_{0}^{2}} \\{\left( {k_{1}k_{2}} \right)w_{0}^{3}}\end{bmatrix}} & (11)\end{matrix}$
 5. The design method for the active disturbance rejectionroll controller of the vehicle under the disturbance of the complex seaconditions according to claim 3, wherein in step 2.2, the LSEF adopts acontroller of a linear proportional and derivative (PD) combination,z₁→y, z₂→{dot over (y)}; and a control law is:u ₀ =k _(p)(z _(c) −z ₁)−k _(d) z ₂   (12) where, u₀ is a final controloutput, z_(c) is an expected roll angle, z₁ is a roll angle of thevehicle in a current state, and z₂ is an angular velocity in roll of thevehicle in the current state; a closed-loop transfer function is:$\begin{matrix}{{G(s)} = \frac{k_{p}}{s^{2} + {k_{d}s} + k_{p}}} & (13)\end{matrix}$ where k_(p) and k_(d) are controller parameters needing tobe designed, and, by selecting the pole of the transfer function of thecontroller and placing the pole at different positions w_(c) andk₃w_(c), w_(c)>1, k₃>1, the controller parameters are obtained asfollows:k _(p) =k ₃ w _(c) ²k _(d)=(k ₃+1)w _(c)   (14) after parametric design, six parameters tobe adjusted in the ADRC are w₀, w_(c), b₀, k₁, k₂, k₃, wherein w₀ is thepole of the extended state observer, w_(c) is a pole of the controller,b₀ is a control coefficient, k₁ and k₂ are the pole placementcoefficients of the extended state observer, and k₃ is a pole placementcoefficient of the controller.